Mounting datum of surgical instrument

ABSTRACT

An instrument sterile drape includes a plastic sheet and an instrument sterile adapter (ISA) coupled to the plastic sheet. The ISA includes a bottom plate located on a first side of the plastic sheet and a top plate located on a second side of the plastic sheet and joined to the bottom plate. The bottom plate includes a mounting surface that provides a first datum plane for mounting the ISA on a carriage that includes actuators and a plurality of landing pads that extend through the top plate to provide a second datum plane for a surgical instrument coupled to the ISA such that a distance between the carriage and the surgical instrument is controlled only by the bottom plate. The instrument sterile drape may include a pouch shaped to fit around the carriage with the ISA capturing the pouch between the top and bottom plates.

This application is a 371 of international application numberPCT/US15/020885 filed Mar. 17, 2015, and claims benefit of the followingearlier filed applications:

-   -   U.S. 61/954,497 17 Mar. 2014 (17 Mar. 2014)    -   U.S. 61/954,502 17 Mar. 2014 (17 Mar. 2014)    -   U.S. 61/954,557 17 Mar. 2014 (17 Mar. 2014)    -   U.S. 61/954,571 17 Mar. 2014 (17 Mar. 2014)    -   U.S. 61/954,595 17 Mar. 2014 (17 Mar. 2014)    -   U.S. 62/019,318 30 Jun. 2014 (30 Jun. 2014)    -   U.S. 62/103,991 15 Jan. 2015 (15 Jan. 2015)    -   U.S. 62/104,306 16 Jan. 2015 (16 Jan. 2015)        Each of these applications is specifically incorporated herein        by reference to the greatest extent permitted.

FIELD

Embodiments of the invention relate to the field of field of surgicaldrapes; and more specifically, to surgical drapes for teleoperatedactuators with provisions for providing a mounting datum for attachedsurgical instruments.

BACKGROUND

Minimally invasive medical techniques have been used to reduce theamount of extraneous tissue which may be damaged during diagnostic orsurgical procedures, thereby reducing patient recovery time, discomfort,and deleterious side effects. Traditional forms of minimally invasivesurgery include endoscopy. One of the more common forms of endoscopy islaparoscopy, which is minimally invasive inspection or surgery withinthe abdominal cavity. In traditional laparoscopic surgery, a patient'sabdominal cavity is insufflated with gas, and cannula sleeves are passedthrough small (approximately 12 mm) incisions in the musculature of thepatient's abdomen to provide entry ports through which laparoscopicsurgical instruments can be passed in a sealed fashion.

The laparoscopic surgical instruments generally include a laparoscopefor viewing the surgical field and surgical instruments having endeffectors. Typical surgical end effectors include clamps, graspers,scissors, staplers, and needle holders, for example. The surgicalinstruments are similar to those used in conventional (open) surgery,except that the working end or end effector of each surgical instrumentis separated from its handle by an approximately 30 cm. long extensiontube, for example, so as to permit the operator to introduce the endeffector to the surgical site and to control movement of the endeffector relative to the surgical site from outside a patient's body.

In order to provide improved control of the end effector, it may bedesirable to control the surgical instrument with teleoperatedactuators. The surgeon may operate controls on a console to indirectlymanipulate the instrument that is connected to the teleoperatedactuators. The surgical instrument is detachably coupled to theteleoperated actuators so that the surgical instrument can be separatelysterilized and selected for use as needed instrument for the surgicalprocedure to be performed. The surgical instrument may be changed duringthe course of a surgery.

Performing surgery with teleoperated surgical instruments creates newchallenges. One challenge is the need to maintain the region adjacentthe patient in a sterile condition. However, the motors, sensors,encoders and electrical connections that are necessary to control thesurgical instruments typically cannot be sterilized using conventionalmethods, e.g., steam, heat and pressure or chemicals, because they wouldbe damaged or destroyed in the sterilization process.

Another challenge with teleoperated surgery systems is that a number ofconnections are required between the surgical instrument and theteleoperated actuator and its controller. Connections are required totransmit the actuator forces, electrical signals, and data. This makesthe attachment of the surgical instrument to the teleoperated actuatorand its controller complex.

Still another challenge with servo actuated teleoperated surgery systemsis that an operating room is not an ideal environment for preparingprecision mechanical assemblies.

It is desirable to provide an effective sterile barrier interfacebetween a surgical system's teleoperated actuator and a surgicalinstrument controlled by the actuator. Although known sterile barrierinterfaces have been effective, the need to improve work flow forpatient-side surgical personnel and to accommodate advances inteleoperated surgical instrument designs and capabilities requiresimproved sterile interfaces. Among the required improvements are anability to quickly, easily, and reliably mount the surgical instrumentto the actuator's mechanical drive elements with a known distancebetween the instrument and the actuator despite the intervening sterilebarrier interface (with its associated sterile barrier drape).

SUMMARY

An instrument sterile drape includes a plastic sheet and an instrumentsterile adapter (ISA) coupled to the plastic sheet. The ISA includes abottom plate located on a first side of the plastic sheet and a topplate located on a second side of the plastic sheet and joined to thebottom plate. The bottom plate includes a mounting surface that providesa first datum plane for mounting the ISA on a carriage that includesactuators and a plurality of landing pads that extend through the topplate to provide a second datum plane for a surgical instrument coupledto the ISA such that a distance between the carriage and the surgicalinstrument is controlled only by the bottom plate. The instrumentsterile drape may include a pouch shaped to fit around the carriage withthe ISA capturing the pouch between the top and bottom plates.

Other features and advantages of the present invention will be apparentfrom the accompanying drawings and from the detailed description thatfollows below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by referring to the followingdescription and accompanying drawings that are used to illustrateembodiments of the invention by way of example and not limitation. Inthe drawings, in which like reference numerals indicate similarelements:

FIG. 1 is a view of an illustrative patient-side portion 100 of ateleoperated surgical system.

FIG. 2 is a side view of a surgical instrument for use with ateleoperated actuator.

FIG. 3 is a perspective view of a setup joint.

FIG. 4 is a perspective view of a strut portion of the setup joint shownin FIG. 3.

FIG. 5 is a perspective view of a portion of a sterile drape.

FIG. 6 is a perspective view of a control surface of a carriage, aninstrument sterile adapter (ISA), and a surgical instrument.

FIG. 7 is an exploded perspective view of the ISA.

FIG. 8 is a perspective view of a pouch portion of an ISA.

FIG. 9 is a section view of the ISA taken along line 7A-7A in FIG. 7.

FIG. 10 is a section view of a bottom plate of the ISA taken along line7B-7B in FIG. 7.

FIG. 11 is a section view of a portion of the ISA and presence pinstaken along line 7C-7C in FIG. 7.

FIG. 12 is a perspective view of a portion of the ISA and a presence pincircled in FIG. 11.

DESCRIPTION OF EMBODIMENTS

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the invention may bepracticed without these specific details. In other instances, well-knowncircuits, structures and techniques have not been shown in detail inorder not to obscure the understanding of this description.

In the following description, reference is made to the accompanyingdrawings, which illustrate several embodiments of the present invention.It is understood that other embodiments may be utilized, and mechanicalcompositional, structural, electrical, and operational changes may bemade without departing from the spirit and scope of the presentdisclosure. The following detailed description is not to be taken in alimiting sense, and the scope of the embodiments of the presentinvention is defined only by the claims of the issued patent.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper”, and the like may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(e.g., rotated 90 degrees or at other orientations) and the spatiallyrelative descriptors used herein interpreted accordingly.

As used herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising” specify the presence of stated features, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, steps, operations,elements, components, and/or groups thereof.

FIG. 1 is a view of an illustrative patient-side portion 100 of ateleoperated surgical system, in accordance with embodiments of thepresent invention. The patient-side portion 100 includes supportassemblies 110 and one or more surgical instrument manipulators 112 atthe end of each support assembly. The support assemblies optionallyinclude one or more unpowered, lockable setup joints that are used toposition the surgical instrument manipulator(s) 112 with reference tothe patient for surgery. As depicted, the patient-side portion 100 restson the floor. In other embodiments the patient-side portion may bemounted to a wall, to the ceiling, to the operating table 126, whichalso supports the patient's body 122, or to other operating roomequipment. Further, while the patient-side portion 100 is shown asincluding four manipulators 112, more or fewer manipulators 112 may beused. Still further, the patient-side portion 100 may consist of asingle assembly as shown, or it may include two or more separateassemblies, each optionally mounted in various possible ways.

Each surgical instrument manipulator 112 supports one or more surgicalinstruments 120 that operate at a surgical site within the patient'sbody 122. Each manipulator 112 may be provided in a variety of formsthat allow the associated surgical instrument to move with one or moremechanical degrees of freedom (e.g., all six Cartesian degrees offreedom, five or fewer Cartesian degrees of freedom, etc.). Typically,mechanical or control constraints restrict each manipulator 112 to moveits associated surgical instrument around a center of motion on theinstrument that stays stationary with reference to the patient, and thiscenter of motion is typically located to be at the position where theinstrument enters the body.

The term “surgical instrument” is used herein to describe a medicaldevice configured to be inserted into a patient's body and used to carryout surgical or diagnostic procedures. The surgical instrument typicallyincludes an end effector associated with one or more surgical tasks,such as a forceps, a needle driver, a shears, a bipolar cauterizer, atissue stabilizer or retractor, a clip applier, an anastomosis device,an imaging device (e.g., an endoscope or ultrasound probe), and thelike. Some surgical instruments used with embodiments of the inventionfurther provide an articulated support (sometimes referred to as a“wrist”) for the end effector so that the position and orientation ofthe end effector can be manipulated with one or more mechanical degreesof freedom in relation to the instrument's shaft. Further, many surgicalend effectors include a functional mechanical degree of freedom, such asjaws that open or close, or a knife that translates along a path.Surgical instruments may also contain stored (e.g., on a semiconductormemory inside the instrument) information that may be permanent or maybe updatable by the surgical system. Accordingly, the system may providefor either one-way or two-way information communication between theinstrument and one or more system components.

A functional teleoperated surgical system will generally include avision system portion (not shown) that enables the operator to view thesurgical site from outside the patient's body 122. The vision systemtypically includes a surgical instrument that has a video-image-capturefunction 128 (a “camera instrument”) and one or more video displays fordisplaying the captured images. In some surgical system configurations,the camera instrument 128 includes optics that transfer the images fromthe distal end of the camera instrument 128 to one or more imagingsensors (e.g., CCD or CMOS sensors) outside of the patient's body 122.Alternatively, the imaging sensor(s) may be positioned at the distal endof the camera instrument 128, and the signals produced by the sensor(s)may be transmitted along a lead or wirelessly for processing and displayon the video display. An illustrative video display is the stereoscopicdisplay on the surgeon's console in surgical systems commercialized byIntuitive Surgical, Inc., Sunnyvale, Calif.

A functional teleoperated surgical system will further include a controlsystem portion (not shown) for controlling the movement of the surgicalinstruments 120 while the instruments are inside the patient. Thecontrol system portion may be at a single location in the surgicalsystem, or it may be distributed at two or more locations in the system(e.g., control system portion components may be in the system'spatient-side portion 100, in a dedicated system control console, or in aseparate equipment rack). The teleoperated master/slave control may bedone in a variety of ways, depending on the degree of control desired,the size of the surgical assembly being controlled, and other factors.In some embodiments, the control system portion includes one or moremanually-operated input devices, such as a joystick, exoskeletal glove,a powered and gravity-compensated manipulator, or the like. These inputdevices control teleoperated motors which, in turn, control the movementof the surgical instrument.

The forces generated by the teleoperated motors are transferred viadrivetrain mechanisms, which transmit the forces from the teleoperatedmotors to the surgical instrument 120. In some telesurgical embodiments,the input devices that control the manipulator(s) may be provided at alocation remote from the patient, either inside or outside the room inwhich the patient is placed. The input signals from the input devicesare then transmitted to the control system portion. Persons familiarwith telemanipulative, teleoperative, and telepresence surgery will knowof such systems and their components, such as the da Vinci® SurgicalSystem commercialized by Intuitive Surgical, Inc. and the Zeus® SurgicalSystem originally manufactured by Computer Motion, Inc., and variousillustrative components of such systems.

As shown, both the surgical instrument 120 and an optional entry guide124 (e.g., a cannula in the patient's abdomen) are removably coupled tothe distal end of a manipulator 112, with the surgical instrument 120inserted through the entry guide 124. Teleoperated actuators in themanipulator 112 move the surgical instrument 120 as a whole. Themanipulator 112 further includes an instrument carriage 130. Thesurgical instrument 120 is detachably connected to the carriage 130. Theteleoperated actuators housed in the carriage 130 provide a number ofcontroller motions which the surgical instrument 120 translates into avariety of movements of the end effector on the surgical instrument.Thus the teleoperated actuators in the carriage 130 move only one ormore components of the surgical instrument 120 rather than theinstrument as a whole. Inputs to control either the instrument as awhole or the instrument's components are such that the input provided bya surgeon to the control system portion (a “master” command) istranslated into a corresponding action by the surgical instrument (a“slave” response).

FIG. 2 is a side view of an illustrative embodiment of the surgicalinstrument 120, comprising a distal portion 250 and a proximal controlmechanism 240 coupled by an elongate tube 210. The distal portion 250 ofthe surgical instrument 120 may provide any of a variety of endeffectors such as the forceps 254 shown, a needle driver, a cauterydevice, a cutting tool, an imaging device (e.g., an endoscope orultrasound probe), or a combined device that includes a combination oftwo or more various tools and imaging devices. In the embodiment shown,the end effector 254 is coupled to the elongate tube 210 by a “wrist”252 that allows the orientation of the end effector to be manipulatedwith reference to the instrument tube 210.

FIG. 3 is a perspective view of an arm that extends from a setup joint110. The arm supports the carriage 130 which in turn supports thesurgical instrument 120 on a strut 310. In preparation for surgery, thesetup joint is covered with a sterile drape 300. The sterile drapeprotects the arm from contamination and provides a sterile surfacearound the arm. The majority of the sterile drape 300 is a plasticsheet, which may be in the form of a tube or bag, that covers the arm.For example, a single layer thermoplastic polyurethane (TPU) or othersuitable material may be used for the plastic sheet. A lubricant may becompounded in to reduce the tackiness of the plastic. The sheet may beabout 100 micrometers (0.004 inch) thick.

FIG. 4 is a perspective view of the strut 310 portion of the arm thatsupports the carriage 130. A spar 402 positions the carriage 130 on thestrut 310. The sterile drape is not shown to allow the carriage 130 tobe seen more clearly. A surface 400 of the carriage provides a number ofmechanical and electrical interfaces to communicate mechanical motionand data signals between the control system, the actuators, and thesurgical instrument. It will be appreciated that the connections to thesurgical instrument may require a penetration through the sterile drape.It is difficult to provide a penetration through the plastic sheet thatis compatible with the connections between the carriage 130 and asurgical instrument. Further, the carriage 130 is shaped to allow theelongate tube 210 (FIG. 2 of the surgical instrument 120 to pass throughan indentation 410 along a side of the carriage. It is difficult todrape the carriage with the plastic sheet due to the shape of thecarriage and because it projects from the strut 310.

FIG. 5 is a perspective view of the portion of the sterile drape that isconstructed to be placed around the carriage 130. The sterile drapeincludes three portions. The first portion is the plastic sheet 300described above. The second portion is a pouch 500 shaped to fit aroundthe carriage 130. The third portion is a largely rigid instrumentsterile adapter (ISA) 510 that engages the control features 400 of thecarriage 130 and provides a sterile counterpart of the control featuresfor connection to a surgical instrument. Each of the three portions ofthe sterile drape overlaps and seals against the adjacent portion sothat the three portions form a continuous barrier. The sterile drape isa disposable assembly.

The pouch 500 may be made from a materials such as low densitypolyethylene (LDPE), ethylene-vinylacetate copolymers (EVA), and/orthermoplastic urethane (TPU), which may be the same material used forthe plastic sheet 300 but with a greater thickness. Other suitablematerials may be used for the pouch. The pouch 500 may be fabricatedfrom a plastic sheet of an appropriate thickness by a suitable processsuch as heat-forming, thermo-forming, or vacuum-forming. The pouch 500may be flexible but it should return to its original shape when notsubject to stress. The pouch 500 provides a portion of the drape that isa loose form fit around the carriage 130 to provide a clear work spacefor the actuators and the surgical instrument. There may be certainareas where the pouch 500 is more closely fitted to the carriage 130,such as the region 410 where a shaft of a surgical instrument passes thecarriage. It may be desirable to form the pouch 500 from a transparentor translucent material so that features of the carriage 130, such asindicator lights, can be seen through the pouch. In some embodiments,the pouch may be formed of two or more parts. For example, part of thepouch may be formed from a more rigid material and part of the pouch maybe formed from a more flexible material.

An aperture 520 is formed in the plastic sheet 300 where the pouch 500is joined to the plastic sheet. It is desirable to join the pouch 500 tothe plastic sheet 300 with the pouch positioned over the aperture 520rather than extending through the aperture. The plastic sheet may bejoined to the pouch by any process that is compatible with the materialsof the sheet and the pouch, such as by heat welding or a pressuresensitive adhesive (PSA). The aperture 520 may be formed in the plasticsheet 300 before or after the pouch 500 is joined to the plastic sheet.

FIG. 6 is a perspective view of the control surface 400 of the carriage,the ISA 510 (without the pouch or plastic sheet portions of the steriledrape), and a proximal control mechanism 240 of a surgical instrumentthat has been rotated to show the instrument control surface 242. TheISA 510 is coupled to the control surface 400 of the carriage assuggested by the figure. The ISA 510 provides a control surface thatextends all of the control features of the control surface 400 of thecarriage as a sterile, disposable surface that can receive the proximalcontrol mechanism 240 of the teleoperated surgical instrument and engagethe control features of the instrument control surface 242.

FIG. 7 is an exploded perspective view of the ISA 510. The ISA isassembled by inserting coupler disks 724 into openings 722 in a bottomplate 710 of the ISA. The coupler disks 724 may be retained in theopenings by that passing tabs on the disks through keyways in the bottomplate and then turning the disks to misalign the tabs and keyways.Presence pins 600 may be inserted into pockets 712 in the bottom plate710 of the ISA. Flux couplers 704 may be coupled over openings 702 in atop plate 700 of the ISA.

FIG. 8 is a perspective view of the pouch 500. The pouch provides anopening 802 through which the control features—such as the coupler disks724, the presence pins 600, and the flux coupler 704—communicate betweenthe bottom plate 710 and the top plate 700. The assembled bottom plate710 is placed on a first side of the pouch 500, i.e. the side of thepouch facing the interior of the pouch cavity, adjacent the opening 802.The assembled top plate 700 is placed on an opposing second side of thepouch, i.e. the side of the pouch facing away from the interior of thepouch cavity, adjacent the opening 802. The pouch 500 is capturedbetween the top plate 700 and the bottom plate 710, which may be joinedtogether by various methods. One method of joining the top plate 700 andthe bottom plate 710 is passing pins between the top and bottom platesand through the pouch and heat staking the pins to form a permanentassembly. Other suitable methods of joining the top and bottom platesinclude ultrasonic welding, pressure sensitive adhesives (PSA), liquidadhesives, and snap fits.

Referring again to FIGS. 6 and 7, the top plate 700 may include avertical wall portion 612 that is substantially perpendicular to thecontrol surface of the carriage and substantially parallel to the strut310 (FIG. 4) that supports the carriage 130. The vertical wall portion612 of the ISA may provide a rigid surface that assists in guiding asurgical instrument into engagement with the ISA and protects the softsurfaces of the sterile drape during that procedure. The vertical wallportion 612 may include a rib 614 that engages a corresponding recess616 in a proximal control mechanism 240 of a surgical instrument. Therib 614 may be tapered to provide a tolerant initial engagement with theproximal control mechanism 240 that then guides the instrument to a moreprecise location as the instrument is brought into position to engagethe ISA.

Referring again to FIG. 8, some areas 804 that are retained between thebottom plate 710 and the top plate 700 are narrow. If a flexiblematerial is used to form the pouch 500, the material may not beadequately retained between the bottom plate 710 and the top plate 700because of the pouch material's flexibility and elasticity. A stiffener800 may be coupled to the pouch 500 to provide a relatively inelasticarea that corresponds to the portion of the pouch that is retainedbetween the bottom plate 710 and the top plate 700. The inelastic areamay be formed by co-extruding a sheet having a layer of polyethyleneterephthalate glycol-modified (PETG) and a layer of thermoplasticurethane (TPU). The stiffener 800 may be cut for the co-extruded sheet.The stiffener 800 may be coupled to the pouch 500 by heat welding theTPU surface to the pouch, which may also be formed from TPU. Otherassemblies that provide a flexible pouch 500 with an inelastic area 800that is retained between the bottom plate 710 and the top plate 700 ofthe ISA may also be used. Other embodiments may use a pressure sensitiveadhesive (PSA) or a liquid adhesive to bond the pouch 500 to one or bothof the bottom plate 710 and the top plate 700 to retain the pouchbetween the plates.

FIG. 9 is a section view of the ISA 510 taken along line 7A-7A in FIG.7. Referring to FIG. 6, the carriage may provide a sensor 604 forreading a radio frequency identification (RFID) device contained in asurgical instrument. The RFID device may require that the sensor 604 bevery close to the RFID device because of the presence of metalcomponents nearby. The bottom plate 710 of the ISA may provide a passage900 that allows the sensor 604 to pass through the bottom plate, thestiffener 800, and the pouch 500 to be placed adjacent the top plate 700of the ISA. Further, the area 902 of the top plate 700 that will beadjacent the sensor 604 may be thinned to allow the sensor to be stillcloser to the RFID device in a surgical instrument.

Referring again to FIG. 6, the carriage may provide a flux connection606 that provides a connection for electrical and/or optical signals. Inthe embodiment illustrated, pogo pins 606, spring loaded conductivepins, provide electrical signals to be connected to the surgicalinstrument. The bottom plate 710 of the ISA may provide a passage 910that allows the flux connection 606 to pass through the bottom plate,the stiffener 800, and the pouch 500 to be placed adjacent the top plate700 of the ISA. The area of the top plate 700 that will be adjacent theflux connection may provide openings 912 for a flux connector 904 thatcloses the openings in the top plate to provide a continuous barrierwhile providing a path for the electrical and/or optical signals betweenthe flux connection and the surgical instrument.

FIG. 10 is a section view of the bottom plate 710 of the ISA taken alongline 7B-7B in FIG. 7. It is desirable to position the surgicalinstrument at a known distance from the control surface 400 of thecarriage 130 (FIG. 4). If the surgical instrument is located withrespect to the top plate 700 of the ISA, the dimensional tolerances ofthe bottom plate 710, the stiffener 800, the pouch 500, and the topplate all will affect the position of the surgical instrument, which maynot provide the desired precision of location. The bottom plate 710 mayinclude landing pads 602 that provide the datum plane for the surgicalinstrument. The landing pads 602 extend from the bottom plate 710through the stiffener 800, the pouch 500, and the top plate 700. Thebottom plate 710 may further include mounting surfaces 1000 that providethe datum plane for the mounting of the ISA on the control surface 400of the carriage 130. Since the landing pads 602 and the mountingsurfaces 1000 are opposing parallel surfaces on the solid bottom plate710, the distance between the landing pads and the mounting surfaces canbe controlled with considerable precision. Thus the ISA can position thesurgical instrument at a known distance from the control surface 400 ofthe carriage 130 with precision.

FIG. 11 is a section view of a portion of the top 700 and bottom 710plates of the ISA and presence pins 600 taken along line 7C-7C in FIG.7. The control system may require a signal that indicates when asurgical instrument has been coupled to the ISA 510. The carriage mayprovide spring loaded plungers 608 (FIG. 6) that can be depressed toprovide a signal to the control system. The bottom plate 710 of the ISAmay provide pockets 1104 to receive presence pins 600. Openings 1102 areprovided in the bottom plate 710 so that the spring loaded plungers 608can pass into the pockets 1104 in the bottom plate and lift the presencepins 600 through openings in the top plate 710. The presence pins 600allow a surgical instrument to depress the spring loaded plungers 608 inthe carriage while maintaining a sterile barrier between the surgicalinstrument and the carriage. When a surgical instrument is coupled tothe ISA the presence pins 600 are depressed, perhaps to the positionillustrated in FIG. 11, and the spring loaded plungers 608 are likewisedepressed to provide a signal to the control system indicating that asurgical instrument is coupled to the ISA.

FIG. 12 is a perspective view of a portion of the ISA and a presence pincircled 12 in FIG. 11. As best seen in FIG. 12, the pockets 1104 in thebottom plate 710 may project from the lower surface 1000 of the bottomplate. The protrusions 1106 that house the pockets may extend into thecarriage is spaces around the spring loaded plungers 608. This allowsthe spring loaded plungers to be located below the surface of thecarriage that receives the ISA to protect the spring loaded plungersfrom lateral forces that might damage the plungers.

The protrusions 1106 may be chamfered at the end that enters thecarriage to assist in positioning the ISA on the carriage. Referring toFIG. 6, the guide pin 610 on the control surface 400 of the carriage mayengage a receptacle on the ISA to laterally position that end of the ISAas it is positioned on the carriage. The protrusions 1106, particularlythe protrusion furthest from the vertical wall portion 708 may cooperatewith the guide pin 610 engagement to laterally position the opposite endof the ISA and align it for engagement with the control surface 400 ofthe carriage.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative of and not restrictive on the broad invention, andthat this invention is not limited to the specific constructions andarrangements shown and described, since various other modifications mayoccur to those of ordinary skill in the art. The description is thus tobe regarded as illustrative instead of limiting.

What is claimed is:
 1. An instrument sterile drape comprising: a plasticsheet; and an instrument sterile adapter (ISA) coupled to the plasticsheet, the ISA including a bottom plate located on a first side of theplastic sheet and a top plate located on a second side of the plasticsheet and joined to the bottom plate, the bottom plate including amounting surface that provides a first datum plane for mounting the ISAon a carriage that includes actuators and a plurality of landing padsthat extend through the top plate to provide a second datum plane for asurgical instrument coupled to the ISA such that a distance between thecarriage and the surgical instrument is controlled only by the bottomplate.
 2. The instrument sterile drape of claim 1 wherein the plasticsheet is a single layer of thermoplastic polyurethane about 100micrometers (0.004 of an inch) thick in the form of a tube and theplastic sheet includes a lubricant.
 3. The instrument sterile drape ofclaim 1 further comprising a pouch sealed to a first opening in theplastic sheet, the pouch shaped to fit around the carriage, the pouchincluding a second opening to which the ISA is coupled with the bottomplate located on a first side of the pouch and the top plate located onan opposing second side of the pouch.
 4. The instrument sterile drape ofclaim 3 wherein the pouch is shaped to provide a loose form fit aroundthe carriage.
 5. The instrument sterile drape of claim 3 wherein thepouch is made from a polyurethane.
 6. The instrument sterile drape ofclaim 3 wherein the top plate is joined to the bottom plate by passingpins between the top and bottom plates and through the pouch and heatstaking the pins to form a permanent assembly.
 7. The instrument steriledrape of claim 1 wherein the plurality of landing pads and the mountingsurface are opposing parallel surfaces on the bottom plate.
 8. Theinstrument sterile drape of claim 1 wherein the bottom plate includes apocket with a third opening in a first surface of the bottom platefurthest from the top plate, and the top plate includes a fourth openingin a second surface of the top plate furthest from the bottom plate; andthe ISA further includes a presence pin loosely retained in the pocket,a portion of the presence pin extending through the fourth opening. 9.The instrument sterile drape of claim 8 wherein at least a portion ofthe pocket is housed within a protrusion that extends from the firstsurface of the bottom plate.
 10. The instrument sterile drape of claim 9wherein the protrusion is a cylindrical protrusion and an end of thecylindrical protrusion furthest from the first surface is chamfered. 11.A method for assembling an instrument sterile drape, the methodcomprising: providing a plastic sheet; joining a bottom plate located ona first side of the plastic sheet to a top plate located on an oppositesecond side of the plastic sheet as part of an instrument sterileadapter (ISA), the bottom plate including a mounting surface thatprovides a first datum plane for mounting the ISA on a carriage thatincludes actuators; and extending a plurality of landing pads that areincluded in the bottom plate through the plastic sheet and the top plateto provide a second datum plane for a surgical instrument coupled to theISA such that a distance between the carriage and the surgicalinstrument is controlled only by the bottom plate.
 12. The method ofclaim 11 wherein the plastic sheet is a single layer of thermoplasticpolyurethane about 100 micrometers (0.004 inch) thick in the form of atube and the plastic sheet includes a lubricant.
 13. The method of claim11 further comprising: creating a first opening in the plastic sheet;forming a pouch to fit around the carriage; sealing the pouch to thefirst opening in the plastic sheet; creating a second opening in thepouch; and joining the bottom plate to the top plate at the secondopening in the pouch.
 14. The method of claim 13 further comprising:placing the bottom plate over the second opening on a first side of thepouch; placing the top plate over the second opening on a second side ofthe pouch opposite the first side; and joining the bottom plate and thetop plate to retain a portion of the pouch between the bottom plate andthe top plate.
 15. The method of claim 14 further comprising: passingpins between the top and bottom plates and through the pouch; and heatstaking the pins to form a permanent assembly.
 16. The method of claim13 wherein the pouch is formed to provide a loose form fit around thecarriage.